1. Field of the Invention
This invention relates to the field of fish lures to be drawn through water using a line, and in particular to a fish lure having periodic variations in lure characteristics caused by ingestion of air.
2. Description of the Prior Art
Various fish lures are known in the art to have some form of longitudinal opening through which water passes as the lure is drawn through the water in a trolling motion. An example of such a device is U.S. Pat. No. 3,705,465-Charney, in which a clear plastic material of a generally tubular shape is provided with external eyes and various devices located inside the hollow body along the flow path. In one embodiment, Charney's lure includes a sealed hollow body having a so-called "knocker" ball that rolls to and fro to audibly attract fish.
It is known to mount flow-diverting mechanisms along the flow path in a hollow lure body, in order to impart a wiggling motion to the lure similar to the swimming motion of a bait fish. Examples of these devices are shown in U.S. Pat. Nos. 1,708,825-Barclay, 2,538,459-Kasmeyer and 2,817,180-Thomas. In Thomas, the diverter is designed to not only wiggle the lure, but to displace the lure transversely from the axis of the line drawing the lure through the water.
Freely-movable diverter mechanisms are also known, some being mounted within the lure and some being external thereto. In U.S. Pat. No. 4,231,179-Hillesand, for example, a tail-wiggling artificial worm is affixed to a line behind a plug having a longitudinal opening, the worm causing the lure to wiggle when trolled. Similarly, U.S. Pat. No. 2,600,437-Siepe teaches a hingeable deflector mounted at the tail of a hollow body. These devices are useful for causing a lure to wiggle or even to make small scale diversions from the axis of the line on which they are drawn. The devices are not effective, however, for making substantial and long-lived changes in the lure's operating characteristics, as might reflect the natural action of a bait fish alternately coming to the surface and diving. Accordingly, the small scale or wiggling diversions are less realistic and less interesting to game fish than they might be. The prior art devices are also somewhat complicated in their structure, increasing the cost of manufacture.
Knocker ball lures, that is lures having movable elements adapted to impact on internal surfaces to cause an attractive noise, are known in various forms. In U.S. Pat. No. 4,203,246 and 3,988,851, both to Sacharnoski, Sr., a glass tube having a plurality of captive free rolling metal balls can be mounted inside a lure to make an attractive noise. The tube and balls according to Sacharnoski can be mounted longitudinally or transversely in the lure, and it appears that the random motions of the lure in the water are relied upon to tilt the tube and cause the balls to roll against the ends of the tube and against one another. In U.S. Pat. No. 4,453,335-Smith, a knocker ball is held captive between pins, and adapted to move transversely rather than longitudinally, in response to oscillations in fluid flow through a hollow lure. In U.S. Pat. Nos. 3,757,455-Strader, propellers are employed to spin a hollow receptacle for a number of noisemaking balls.
Although the foregoing knocker ball devices are effective in making noise, the noise is essentially random, that is, not corresponding to any change in direction of the lure. Inasmuch as the lures operate at a predetermined depth under water, the tonal qualities of the noise remain constant. The fact that the moveable balls tend to change the weight balance of the lure is largely ignored in the prior art teachings and no attempt is made to periodically change tonal qualities, for example by periodic ingestion of air.
According to the invention, a lure is provided that will alternatively dive and surface in a manner that permits a substantial and long-lived change in the lure's running depth. This is provided by means of a stern- or tail-heavy lure that surfaces to ingest air into a longitudinal passage, escape of the air being retarded at a trailing end of the lure. With air trapped at the trailing end, the lure becomes nose-heavy and dives. When the ingested air has escaped, the lure becomes tail-heavy and rises. The alternating balance effect of air bubbles ingested in this manner is made more pronounced by noise-making knocker balls that are movable along the longitudinal axis of the lure, displacement of the knocker balls tending to make the lure even more nose heavy when diving and even more tail heavy when surfacing. The intermittent ingestion of air bubbles also changes the noise emitted by the lure in the water due to an effective change in lure mass and/or resonant characteristics. The lure is relatively uncomplicated in construction and therefore provides an effective solution to many of the problems in the art.